Color silver halide photographic materials rely on coupler compounds to form dyes that make up the image recorded in such materials. Usually a yellow dye-forming coupler will be associated with a blue-sensitive silver halide emulsion layer, a magenta dye-forming coupler will be associated with a green-sensitive silver halide emulsion layer, and a cyan dye-forming coupler will be associated with a red-sensitive silver halide emulsion layer. With color negative materials, the material is exposed to light and processed with a color developer that imagewise forms a silver image and a dye image. The silver image is bleached and solubilized for removal, leaving only a negative color dye image. This image is then used to expose another color negative material to form a positive color dye image. With one common type of color reversal material, the material is exposed and processed with a black-and-white developer to form a negative silver image in each layer. The silver is then bleached and solubilized for removal, leaving a positive imagewise pattern of unexposed silver halide. The material is then chemically fogged and processed in a color developer to form a positive silver and dye image. The silver is then bleached and solubilized for removal, leaving only the positive color dye image.
There are many known classes of compounds that are useful as couplers in photographic materials. 5-Pyrazolone coupler compounds are well-known as magenta dye-forming couplers. Such couplers are described in, for example, James, The Theory of the Photographic Process, MacMillan, 1977.
While 5-pyrazolone compounds are useful dye-forming couplers, photographic materials and compositions utilizing them often do not provide as high a contrast as might be desired. It is thus an object of this invention to provide higher contrast for photographic compositions containing 5-pyrazolone coupler compounds.